It doesn't matter if the client is synced. You should unlock the wallet with the walletpassphrase RPC before trying to sign a transaction. Other than that, maybe you could show more details. What are you typing, and what does the error say? "I failed" isn't helpful.
Here's the random test data I'm using:
From address: xSPPAQsgYTUsiH51xG3u4Shf7Cc7dt5V7g (importprivkey Lo2RApGkaDZDePA347i56Lo4xRNGBwuxUgyQBC5cK9Ea2Kpn2mnt)
To address: xK8vfFyKC4J2SHR2Hhk7whQAaCTGWbEEwW (importprivkey LnE8nFjSGVKhxoo5rxNZnQU31zT2JnDmVNsEEXoA8tq1HoXtJ4DC)
Amount: 3.5 CLAM
TX in which they were received: 71f2cbe9ff92b8c62a2bcfba5dfc9bc32a2d0c71bf55834e6d884b9ab0de201c
Output in which they were received: 69
By the way, I'm using the console window of the clam-qt.exe client. I'm testing on a Windows VM without network that has never seen any Clam install before (and for every test I revert it back to a previous snapshot).
I just start the exe, import the above keys, restart the exe and go to the console window. There's no password set (at least clam-qt never asked for one).
Here's the screenshot of my attempt:
http://picpaste.com/iYdNPs6T.pngI'm aware that any other Clams would be a tx fee; I'm just trying to get this to work right now, so I don't bother about fees.
